NASA’s Mars rover Curiosity is back in action, after engineers have fixed the software snag which put the robot on a precautionary ‘standby’ mode earlier this week.

“We expect to get back to sample-analysis science by the end of the week,” said Curiosity Mission Manager Jennifer Trosper of NASA’s Jet Propulsion Laboratory (JPL), Pasadena, California.

Curiosity went into a precautionary ‘safe mode’ on March 16, after being sidelined by a computer glitch for the second time in three weeks.

The safe-mode entry was triggered when a command file failed a size-check by the rover’s protective software. Engineers detected a software bug that appended an unrelated file to the file being checked, causing the size mismatch.

Engineers diagnosed the software issue and know how to prevent it from happening again, according to a JPL statement.

Next steps will include checking the rover’s active computer, the B-side computer, by commanding a preliminary free-space move of the arm.

The B-side computer was provided information last week about the position of the robotic arm, which was last moved by the redundant A-side computer.

The rover was switched from the A-side to the B-side by engineers on February 28 in response to a memory glitch on the A-side. The A-side now is available as a back-up if needed.

However, Curiosity only has about two weeks to continue analysing the drill sample it recently collected from a Yellowknife Bay rock, before it is forced to take another break.

Beginning April 4, all commands to the rover will be suspended for four weeks due to solar system geometry of Mars passing nearly directly behind the Sun from Earth’s perspective.

The suspension is a precaution against interference by the Sun corrupting a command sent to the rover.

Back From Far Side of the Sun, Curiosity Rover Gets Ready to Resume Science

A beautiful mosaic stitched together from Curiosity images from before the Mars conjunction, showing the rover’s arm and Mount Sharp in the distance

After a long period of silence, NASA has reestablished its link with the Curiosity and Opportunity rovers and is getting ready to resume science operations on Mars.

The Red Planet has been hidden behind the sun for most of the month of April, meaning that signals sent from here to there could get interrupted or scrambled. The Mars flotilla — which includes the two rovers, two orbiting satellites, the Mars Reconnaissance Orbiter and Mars Odyssey, and ESA’s Mars Express spacecraft – have been on their own for this duration. The rovers have been banned from driving and have mostly been taking routine measurements. Curiosity, for instance, has monitored radiation and atmospheric changes from its position at Gale Crater.

But now the wait is over. Both rovers are reporting healthy status. The smaller and older Opportunity rover, which has been on Mars since 2004, is out of standby mode and executing new instructions from NASA. The first thing in store for Curiosity is a software update.

“From time to time on your laptop, you need to update your operating system,” said geologist John Grotzinger of Caltech, the rover’s project scientist. “Every couple of months we also upload a new version of Curiosity’s flight software and, when it’s convenient, we transition to it.”

The newest 225-million-kilometer software patch will improve the rover’s efficiency. Certain operations, like making sure the robot’s ChemCam wasn’t pointed at the sun, previously required a human at mission control to be in the loop. Such processes are now automated.

The software update won’t go as quickly as getting the newest version of an iPhone app. It will take the rest of the week to make sure everything is properly installed. After that, Curiosity will be ready to resume doing science.

Grotzinger said the science team is looking to document their drill site, perhaps getting some close-up photos and X-ray measurements inside the drill hole. After that, they will probably look to bore another hole about one or two meters from the original drill site to see if there are any mineral variations in the rock.

“Then we’ll make sure there aren’t some last minute things to wrap up and begin our plan to head to Mount Sharp,” said Grotzinger, referring to the 5.5-km-high peak at the center of Gale Crater that is Curiosity’s main target.

The rover hopes to investigate the mountain in order to better understand its watery history and whether or not it could have definitively supported life in the past. Curiosity moves slowly, about the same speed as a crawling baby, so it will take a while to reach Mount Sharp, likely after a few stops at areas of geologic interest. Grotzinger is optimistic that the long trek will begin this summer.

Nasa's Curiosity rover will soon return to a spectacular set of rocks on Mars to confirm their deposition in water billions of years ago.

The Shaler outcrop pictured with Mount Sharp in the distance. This panorama was built from pictures taken by the rover's navigation cameras, and assembled by Ken Kremer and Marco Di Lorezo

This conjunction, as it is known, plays havoc with communications and the robot was forced to park up while the celestial mechanics took their course. But the ability to send commands has now been restored, and scientists have a heavy schedule of tasks they want the rover to work through.

The vehicle is currently sitting in a small depression on the floor of Gale Crater known as Yellowknife Bay. Just before conjunction, it drilled into a mudstone in a rock unit referred to as Sheepbed and found further compelling evidence for a watery past in Gale - sediments that possibly once formed a lakebed.

Curiosity is due to turn its drill again in this mudstone for further analysis before climbing out of Yellowknife Bay and heading for the crater's big central mountain, Aeolis Mons (Mount Sharp).

But almost as soon as it starts that journey, the robot is going to stop at some of the most spectacular rocks seen so far on the mission.

Scientists have mentioned the so-called Shaler outcrop but haven't yet spoken about it in great detail.

Shaler is a classic example of cross-stratification - a structure produced from thin, inclined layers of sediment.

You'll have seen examples in a river or on a beach.

The turbulent flow of water creates undulations in the bed sediments - a series of ripples or dunes that slowly migrate in the direction of the water current.

The sediment grains bouncing along the bed get pushed up the rearward-facing slope (stoss) and then avalanche down the other side (lee).

As they cascade downwards, they form discrete layers that can be preserved over geological time as laminations in the rock.

If you look at the pictures of Shaler taken by Curiosity, you can see how subsequent erosion has taken its toll on this preserved bedform. Layers just a few millimetres thick are now falling out. Thin plates of rock are strewn over the ground.

For anyone about to begin their study of geology, cross-stratification, or cross-bedding, will be one of the first topics to be covered in "sedimentary processes", and Shaler is a beautiful example.

"It's textbook; you could use the Shaler pictures of cross-bedding in an intro-textbook," Prof John Grotzinger, the project scientist on the Curiosity mission, told me.

"For a while Shaler really was a contender to drill. We were discussing it as a team and then we drove down into Sheepbed and thought 'wow, well let's put Shaler off to the side'."

Sedimentary processes at work on Earth are also seen in play on the Red Planet

But scientists will now get a chance to study Shaler in more detail in the coming weeks, using the rover's cameras and survey instruments.

They're keen to establish for sure how those thin layers were built.

At first glance, it might seem obvious that it was through the action of flowing water (fluvial), but the Curiosity team needs to rule out the possibility that these rocks were deposited by the wind (aeolian) or by some kind of surge, such as the fast-moving clouds of gas and rock that will often plummet down the sides of particular types of volcano (a pyroclastic surge).

"Aeolian. That's the one you always have to falsify on Mars because it's a windy planet," says Prof Grotzinger.

This can be done by looking at the size of the rock grains in the layers; and from the pictures taken of Shaler on the way into Yellowknife Bay, it seems the particles are simply too big to have been carried in the wind. Further imagery will confirm that.

There are ways to discount the base surge idea, also, explains Dr Lauren Edgar from Arizona State University.

"If you're migrating faster than you're accumulating, you just preserve the lee side because you're eroding on that stoss side. However, in a pyroclastic surge environment, you often have high rates of accumulation relative to migration, so as the bedform is migrating it is also rapidly accumulating more sediment. This means you tend to get the full stoss-side and lee-side preserved," she told BBC News.

Another check is to look for a diversity of flow directions. A surge deposition will tend to move radially away from a point source. Cross-stratification from water currents, on the other hand, will likely show movement in assorted directions.

To be honest, it's hard to think where a surge might have come from in Gale. There are no volcanoes around.

But Curiosity should nail all this with its return visit to Shaler.

Here's the really clever thing, though, I think. Cross-stratification is one of those rock structures that is so well understood, you can use it to pull out some amazing information about the past environment in which it occurred.

I've mentioned the direction of flow, but you can also determine the depth of the water and the speed of the water - not precisely, but to a good approximation.

Ponder that for a moment. That's information about an environment that existed on another planet millions of kilometres away.

"The other really nice thing," says Prof Sanjeev Gupta, a Curiosity science team-member from Imperial College London, "is that what you're recording at Shaler is perhaps just a few minutes to hours of migration in those dunes, and then that activity has been preserved for billions of years. That's stunning."

Edgar, Grotzinger and Gupta presented their latest thinking about Shaler on a poster at the recent European Geosciences Union General Assembly. Two of their colleagues on the work have some particularly nice web resources related to cross-stratification.

Prof Dawn Sumner from the University of California at Davis describes how the layers are built in a YouTube video. Dr Dave Rubin, at the US Geological Survey, has a collection of animations to show the different forms. And click here to see a tank experiment. Watch the ripples migrate into view from the left.

After landing on the floor of Gale Crater last August, Curiosity drove east. It passed Shaler on its way into Yellowknife Bay. When the rover drives back out in the coming weeks, it will stop at Shaler for a closer look

This map shows the location of "Cumberland," the second rock-drilling target for NASA's Mars rover Curiosity, in relation to the rover's first drilling target, "John Klein," within the southwestern lobe of a shallow depression called "Yellowknife Bay." Cumberland, like John Klein, is a patch of flat-lying bedrock with pale veins and bumpy surface texture. The bumpiness is due to erosion-resistant nodules within the rock, which have been identified as concretions resulting from the action of mineral-laden water.

This second drilling target, called "Cumberland," lies about nine feet (2.75 meters) west of the rock where Curiosity's drill first touched Martian stone in February. Curiosity took the first rock sample ever collected on Mars from that rock, called "John Klein." The rover found evidence of an ancient environment favorable for microbial life. Both rocks are flat, with pale veins and a bumpy surface. They are embedded in a layer of rock on the floor of a shallow depression called "Yellowknife Bay."

This second drilling is intended to confirm results from the first drilling, which indicated the chemistry of the first powdered sample from John Klein was much less oxidizing than that of a soil sample the rover scooped up before it began drilling.

"We know there is some cross-contamination from the previous sample each time," said Dawn Sumner, a long-term planner for Curiosity's science team at the University of California at Davis. "For the Cumberland sample, we expect to have most of that cross-contamination come from a similar rock, rather than from very different soil."

This patch of bedrock, called "Cumberland," has been selected as the second target for drilling by NASA's Mars rover Curiosity. The rover has the capability to collect powdered material from inside the target rock and analyze that powder with laboratory instruments. The favored location for drilling into Cumberland is in the lower right portion of the image.

Although Cumberland and John Klein are very similar, Cumberland appears to have more of the erosion-resistant granules that cause the surface bumps. The bumps are concretions, or clumps of minerals, which formed when water soaked the rock long ago. Analysis of a sample containing more material from these concretions could provide information about the variability within the rock layer that includes both John Klein and Cumberland.

Mission engineers at NASA's Jet Propulsion Laboratory in Pasadena, Calif., recently finished upgrading Curiosity's operating software following a four-week break. The rover continued monitoring the Martian atmosphere during the break, but the team did not send any new commands because Mars and the sun were positioned in such a way the sun could have blocked or corrupted commands sent from Earth.

Curiosity is about nine months into a two-year prime mission since landing inside Gale Crater on Mars in August 2012. After the second rock drilling in Yellowknife Bay and a few other investigations nearby, the rover will drive toward the base of Mount Sharp, a 3-mile-tall (5-kilometers) layered mountain inside the crater.

The patch of windblown sand and dust downhill from a cluster of dark rocks labeled the "Rocknest" site, where eagle-eyed believers think they've uncovered a "space rat."NASA/JPL-Caltech/MSSS

A zoomed-in view of the "Rocksnest" spot; the patch of rocks in question is seen at the lower-left side.NASA/JPL-Caltech/MSSS

An even closer, zoomed-in view of the "Rocksnest" spot; the "rodent" is seen at the top left.NASA/JPL-Caltech/MSSS

Is that a rat on Mars?

A photo from the mast camera on NASA’s Curiosity rover reveals the dusty orange, rock-strewn surface of the Red Planet -- and what starry-eyed enthusiasts claim is a dusty orange rodent hiding among the stones.

The photo, taken Sept. 28, 2012, depicts the “Rocknest” site, where NASA’s rover took a scoopful of sand, tasted it, and determined it was full of weathered basaltic materials -- not unlike Hawaii, the space agency’s scientists said last year.

'Note its lighter color upper and lower eyelids, its nose and cheek areas, its ear, its front leg and stomach.'
- ScottCWaring on the blog UFO Sightings Daily

No word on how the rodent tasted, however.

The “creature” was identified on the UFO Sightings Daily website, where its finder, ScottCWaring, held tight to his opinion: That’s one darn cute rodent on Mars.

“Note its lighter color upper and lower eyelids, its nose and cheek areas, its ear, its front leg and stomach. Looks similar to a squirrel camouflaged in the stones and sand by its colors," he wrote. "Hey, who doesn't love squirrels, right?”

Others pointed out that the similarity in coloring and position mean it was most likely just a rock, fingering the psychology phenomenon known as pareidolia, a propensity to pick out faces from everyday objects and structures.

To take advantage of this psychological phenomenon closer to home, designers at Berlin's Onformative studio developed an algorithm that scans the surface of the earth with Google Maps, picking out geographical structures that are likely to be construed as having face-like features, science blog iO9 recently pointed out.

Their algorithm found faces in fields, mustaches in mountains, hills with actual eyes.

The pale rock in the upper center of this image, about the size of a human forearm, includes a target called "Esperance," which was inspected by NASA's Mars Exploration Rover Opportunity. This image is a composite of three exposures taken by Opportunity's panoramic camera during the 3,262nd Martian day, or sol, of the rover's work on Mars (March 28, 2013).

NASA's Mars rover Opportunity has made perhaps the biggest discovery of its nearly 10-year career, finding evidence that life may have been able to get a foothold on the Red Planet long ago.

The Opportunity rover spotted clay minerals in an ancient rock on the rim of Mars' Endeavour Crater, suggesting that benign, neutral-pH water once flowed through the area, scientists said.

"This is water you could drink," Opportunity principal investigator Steve Squyres of Cornell University told reporters today (June 7), explaining why the rock, dubbed "Esperance," stands out from other water-soaked stones the rover has

"This is water that was probably much more favorable in its chemistry, in its pH, in its level of acidity, for things like prebiotic chemistry — the kind of chemistry that could lead to the origin of life," Squyres added.

A long-lived rover
The golf cart-size Opportunity and its twin, Spirit, landed on the Red Planet in January 2004 on three-month missions to search for signs of past water activity. The robotic explorers found plenty of such evidence (much of it indicating extremely acidic water, however), then just kept rolling along.

Spirit stopped communicating with Earth in 2010 and was declared dead a year later, but Opportunity is still going strong. In August 2011, the six-wheeled robot arrived at the rim of the 14-mile-wide Endeavour Crater, which it has been investigating ever since.

Opportunity has seen signs of clays in Endeavour rocks before, but in nowhere near the concentrations observed in Esperance, researchers said. Overall, Esperance provides strong evidence that ancient Mars was habitable.

"The fundamental conditions that we believe to be necessary for life were met here," Squyres said.

The neutral-pH water that generated the clays probably flowed through the region during the first billion years of Martian history, he added, stressing that it's nearly impossible to pin down the absolute ages of Red Planet rocks without bringing them back to Earth.

Opportunity's latest discovery fits well with one made recently on the other side of the planet by the rover's bigger, younger cousin Curiosity, which found strong evidence that its landing site could have supported microbial life in the ancient past.

Such observations could help scientists map out Mars' transition from a relatively warm and wet world long ago to the cold and dry planet we know today.

"All the details need to be worked out, but the more we look, the more it fits into this kind of broad context," said Opportunity deputy principal investigator Ray Arvidson of Washington University in St. Louis

During Barack Obama’s first inauguration as president in 2009, photographer David Bergman snapped hundreds of photos to build a stunning mosaic of the event, comprising more than one billion pixels in total. Users of the clickable, zoomable Gigapan platform (where the inauguration mosaic has attracted more than 15 million views) dove into the image to pull out any number of embedded details, from celebrities in the crowd to an apparently dozing Clarence Thomas.

Now a new 1.3-billion-pixel image of the surface of Mars should keep curious clickers occupied for a while, even though the chances of spotting Beyoncé or a sleepy Supreme Court justice are nil. NASA released the ultradetailed Gigapan mosaic, built up from roughly 900 individual images, on June 19.

The images in the mosaic come from the space agency’s Curiosity Rover, currently scouring Gale Crater on the Red Planet in search of evidence of past habitable environments. The rover’s telephoto camera acquired most of the snapshots, according to a NASA statement, with supplemental images from a wide-angle camera on the rover’s mast and a few robot selfies from Curiosity’s navigation camera.

The mosaic shows Curiosity’s environs in late 2012, when the rover was parked at a sandy location called Rocknest. That is where Curiosity first deployed the scoop at the end of its robotic arm to sample the fine-grained Martian soil and fired up its suite of onboard instruments to chemically analyze the material.

In this presentation of the Mars mosaic, NASA has helpfully supplied some annotations of significant sites, such as the rover’s landing area and its ultimate destination, Mount Sharp. But once you familiarize yourself with the image, I recommend exploring it in full-screen panorama mode to fully appreciate the astonishing detail.

This view from the left Navigation Camera of NASA's Mars Rover Curiosity looks back at wheel tracks made during the robot's first drive toward Mount Sharp on July 4, 2013. The base of Mount Sharp, which lies about 5 miles away, is Curiosity's main destination.

NASA's Mars rover Curiosity has set out on its first big road trip, a long journey that will traverse miles of Red Planet scenery over the course of the next year or so.

The 1-ton Curiosity rover took its first steps toward the foothills of Mount Sharp — a mysterious mountain that rises 3.4 miles (5.5 kilometers) into the Red Planet sky — on July 4, then made another drive in that direction on Sunday (July 7), NASA officials said.

Curiosity is headed toward a spot about 5 miles (8 km) away that will afford it access to Mount Sharp's lower reaches. This area is the rover's ultimate science destination; the mission team wants Curiosity to climb up through the mountain's foothills, reading the Red Planet's history like a book as it goes.

Mount Sharp "exposes many layers where scientists anticipate finding evidence about how the ancient Martian environment changed and evolved," NASA officials wrote in a mission update today (July 8).

The two recent drives mark a big shift for Curiosity, which hadn't strayed far from its landing site since touching down inside Mars' 96-mile-wide (154 km) Gale Crater on Aug. 5, 2012, kicking off a two-year surface mission to determine if Mars has ever been capable of supporting microbial life.

The six-wheeled robot accomplished a great deal without putting too much wear on its wheels. In March, for example, mission scientists announced that Curiosity had already checked off its main goal, finding that a spot called Yellowknife Bay was indeed habitable billions of years ago.

The rover team took some time afterward to confirm and extend this discovery, and then completed a few other tasks near the landing site before hitting the road for Mount Sharp on July 4 with a 59-foot (18 meters) drive. The July 7 drive measured 131 feet (40 m), researchers said.

Mission officials have estimated that the trek to Mount Sharp will take about a year, though they stress that there is no rigid timeline. Progress will depend on what Curiosity finds along the way, they say.

"We are on a mission of exploration," Curiosity project manager Jim Erickson, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., told reporters last month. "If we come across scientifically interesting areas, we are going to stop and examine them before continuing the journey."

The car-size rover's top speed across hard, flat ground is about 0.09 mph (0.14 km/h).

NASA's Curiosity Mars rover captured this image with its left front Hazard-Avoidance Camera (Hazcam) just after completing a drive that took the mission's total driving distance past the 1 kilometer (0.62 mile) mark. Image released July 17, 2013.

"When I saw that the drive had gone well and passed the kilometer mark, I was really pleased and proud," rover driver Frank Hartman, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. "Hopefully, this is just the first of many kilometers to come."

Curiosity is in the early stages of a long trek to the base of Mount Sharp, which rises 3.4 miles (5.5 km) into the Red Planet sky. The targeted foothills lie about 5 miles (8 km) from Curiosity's current location as the crow flies, and it will likely take the six-wheeled robot — which has a top speed of 0.09 mph (0.14 km/h) — about a year to cover the ground, mission team members have said. Curiosity touched down inside Mars' 96-mile-wide (154 km) Gale Crater on Aug. 5, 2012, kicking off a planned two-year surface mission to determine if the Red Planet has ever been capable of supporting microbial life.

The car-size robot didn't stray far in its first 11 months on Mars, finding happy scientific hunting grounds close to its landing site. Indeed, mission scientists announced in March that Curiosity had already accomplished its primary goal, finding that an area called Yellowknife Bay was habitable billions of years ago. But Mount Sharp's lower reaches have long been Curiosity's ultimate destination. The mission team wants Curiosity to read the history of Mars' changing environmental conditions like a book as the robot climbs up through Mount Sharp's many layers.

The long haul to Mount Sharp should vault Curiosity past NASA's Spirit rover, which logged 4.8 miles (7.7 km) on the surface of Mars between 2004 and 2010. But Curiosity will still be a distant second to Spirit's twin, Opportunity, whose odometer reads 23.35 miles (37.58 km) — and counting.

The golf-cart-size Opportunity, which is currently making its way toward a site called Solander Point to wait out the Martian winter, holds the American record for distance driven on the surface of another world. But the overall champ is the Soviet Union's remote-controlled Lunokhod 2 rover, which tallied 26 miles (42 km) on the moon back in 1973.

This set of three images taken three seconds apart by NASA's Curiosity rover shows the larger of Mars' two moons, Phobos, passing in front of the sun on Aug. 17, 2013

NASA's Mars rover Curiosity has captured the sharpest-ever images of a solar eclipse as seen from the Red Planet.

The 1-ton Curiosity rover snapped pictures with its telephoto lens as Phobos, the larger of Mars' two tiny moons, blotted out much of the solar disk on Aug. 17.

"This event occurred near noon at Curiosity's location, which put Phobos at its closest point to the rover, appearing larger against the sun than it would at other times of day," Mark Lemmon of Texas A&M University, a co-investigator for Curiosity's Mastcam instrument, said in a statement. "This is the closest to a total eclipse of the sun that you can have from Mars."

Phobos does not completely cover the sun as seen from the Red Planet's surface, so the Aug. 17 event was an annular or "ring of fire" eclipse, like the one that wowed skywatchers here on Earth from Australia to Hawaii in May of this year.

Phobos is just 14 miles (22 kilometers) wide on average, and the other Martian moon, Deimos, is even smaller. Many scientists think both natural satellites are asteroids that were captured by the Red Planet's gravity long ago.

The tiny Phobos appears to take a relatively big bite out of the sun because the moon orbits so close to Mars — just 3,700 miles (6,000 kilometers) from the planet's surface. Earth's much larger moon, by contrast, zips around our planet at an average distance of 239,000 miles (384,600 km)

NASA's Curiosity rover has found yet more evidence of ancient Martian water, this time during a recent pit stop along the way toward a huge Red Planet mountain.

The 1-ton Curiosity rover paused to examine a few rocks late last week, making the first of five planned science stops en route to the 3.4-mile-high (5.5 kilometers) Mount Sharp. The break was fruitful, returning further signs of long-ago liquid water, researchers said.

"We examined pebbly sandstone deposited by water flowing over the surface, and veins or fractures in the rock," Curiosity science team member Dawn Sumner, of the University of California, Davis, said in a statement. "We know the veins are younger than the sandstone because they cut through it, but they appear to be filled with grains like the sandstone."

Curiosity landed inside Mars' Gale Crater in August 2012 to determine if the Red Planet has ever been capable of supporting microbial life. The six-wheeled robot checked off that main mission goal this past March, finding that a location near its landing site called Yellowknife Bay was indeed wet and habitable billions of years ago.

In July, Curiosity set out on the 5.3-mile (8.6 km) trek to Mount Sharp, which has been the rover's primary destination since before its November 2011 launch. Researchers want Curiosity to climb up through the mountain's foothills, studying its many layers for clues about the Red Planet's changing environmental conditions.

The rover team also wants to understand the geology of the area between Yellowknife Bay and Mount Sharp, so they planned out investigations at five "waypoints" along the route. The first came Thursday (Sept. 19) at an outcrop scientists dubbed "Darwin."

"We want to understand the history of water in Gale Crater. Did the water flow that deposited the pebbly sandstone at Waypoint 1 occur at about the same time as the water flow at Yellowknife Bay?" Sumner said.

"If the same fluid flow produced the veins here and the veins at Yellowknife Bay, you would expect the veins to have the same composition," Sumner added. "We see that the veins are different, so we know the history is complicated. We use these observations to piece together the long-term history."

This mosaic of four images taken by the Curiosity rover's Mars Hand Lens Imager camera on Sept. 21, 2013 shows detailed texture in a ridge of rock at a location called "Darwin" inside Gale Crater.

Curiosity spent four days studying the rocks at Darwin, then resumed the journey to Mount Sharp on Sunday (Sept. 22) with a 75-foot (22.8 meter) drive. Curiosity has now covered about 20 percent of the distance from Yellowknife Bay to Mount Sharp, researchers said.

"There's a trade-off between wanting to reach Mount Sharp as soon as we can and wanting to chew on rocks all along the way," Curiosity science team member Kenneth Williford, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement. "Our team of more than 450 scientists has set the priority on getting to Mount Sharp, with these few brief waypoint stops."

One of the first things Curiosity did on the red planet was scoop up some stuff from a patch of sand and dust called Rocknest. (Scientists thought it looked like a little nest for rocks, deputy director of NASA's Goddard Space Flight Center, Laurie Leshin, told the Science podcast.) The rover then examined its Martian soil sample using its ChemCam, CheMin and Sample Analysis at Mars (SAM) instruments.

In one of its analyses, Curiosity heated a sample of soil, about half the size of a baby aspirin, to about 835 degrees Celsius (about 1,535 degrees Fahrenheit). At that temperature, the minerals in the soil break down and release volatile gases. A team of international scientists found water vapor, sulfur dioxide, carbon dioxide and oxygen in the sample, in that order of abundance.

So a good amount of the sample—about 1.5 percent to 3 percent by weight—was water. "To me, that's interesting because of the good resource for potential human explorers," Leshin says. "Two percent water means that if you had, say, a square foot of this—or, a cubic foot, sorry—of this soil and heated it up, you could get about two pints of water out of it." Earth's dirt has about 10 times as much water as Mars'.

One recurring theme from this and other soil analyses: Curiosity and its predecessors, including Pathfinder, Spirit and Opportunity, all pretty much found the same soil composition in different Martian locations. This suggests that water-containing soil is available everywhere on Mars. It could also mean some process on Mars is mixing its dirt evenly across its surface, or that the composition of the planet's crust is similar everywhere.

Killer dirt
The other gases from the heating analysis told scientists about what minerals appeared in Martian soil. There was some bad news for any future Mars visitors. The oxygen was released with chlorine gas, which indicates a small fraction of the soil contains perchlorate, which is toxic if ingested. "It's good to know now that it's there," Leshin says, "so we can plan for when humans go to Mars and there's dust everywhere. How are we going to deal with that issue?"

No organics
Curiosity did not find any so-called organic compounds, a name that doesn't necessarily mean the compounds come from living sources. Instead, organic compounds contain elements, including carbon, that scientists consider to be the building blocks of life. Such compounds may be important to future Mars explorers.

The surface of Mars is exposed to a lot of radiation and other harsh conditions, Leshin says, so scientists are still holding out hope that the planet has organic compounds tucked away deeper underground. Curiosity is equipped with a drill to find out.

An unusual rock

On its 43rd Mars-day, or sol, after landing, Curiosity ran into a pyramid-shaped rock that is unlike any other Martian rock humans have ever found. Scientists named the rock Jake Matijevic, after Curiosity's former lead surface operations systems engineer, who died in 2012.

An analysis found Jake_M's proportions of minerals is different from other Martian rocks. However, the rock does look a lot mugearites on Earth, which are a rare type of rock that appear on ocean islands and in continental rifts (Glamorous). Jake_M is so similar to Earthly mugearites, the research team wrote in their paper that if they'd found Jake_M on Earth, they wouldn't know it came from Mars. Mugearites—and Jake_M—are igneous rocks, which means they formed from magma. (Other missions have found other igneous rocks on Mars, but not mugearite-like ones.)

The team used Jake_M's chemistry to hypothesize how it could have formed. It would have required either a high amount of water in the magma, or high pressure, or both. That's evidence that there may be some water under Mars' crust.

More dirt on MarsWhere is Curiosity now?
The little rover that could is still in the Gale Crater, moving as fast as it can toward Mount Sharp. Mount Sharp has geologic layers that may tell scientists more about Mars' history. The mountain may also contain organic compounds.

There are five planned rest stops along the way, during which Curiosity will take samples and perform more science. The rover recently passed Waypoint 1.

A mosaic of four images taken by the Curiosity rover on its way to Mount Sharp, on its 400th Mars-day (sol), September 21, 2013, on Earth. NASA/JPL-Caltech/MSSS

SA's Mars rover Curiosity is a mosaic of photos taken by the rover's Mars Hand Lends Imager taken on Sol 85, the rover's 85th Martian day, as Curiosity was sampling rocks at a stop dubbed Rocknest in Gale Crater. Image released Sept. 26, 2013

Future Mars explorers may be able to get all the water they need out of the red dirt beneath their boots, a new study suggests.

NASA's Mars rover Curiosity has found that surface soil on the Red Planet contains about 2 percent water by weight. That means astronaut pioneers could extract roughly 2 pints (1 liter) of water out of every cubic foot (0.03 cubic meters) of Martian dirt they dig up, said study lead author Laurie Leshin, of Rensselaer Polytechnic Institute in Troy, N.Y.

"For me, that was a big 'wow' moment," Leshin told SPACE.com. "I was really happy when we saw that there's easily accessible water here in the dirt beneath your feet. And it's probably true anywhere you go on Mars."

The new study is one of five papers published in the journal Science today (Sept. 26) that report what researchers have learned about Martian surface materials from the work Curiosity did during its first 100 days on the Red Planet.

Soaking up atmospheric water
Curiosity touched down inside Mars' huge Gale Crater in August 2012, kicking off a planned two-year surface mission to determine if the Red Planet could ever have supported microbial life. It achieved that goal in March, when it found that a spot near its landing site called Yellowknife Bay was indeed habitable billions of years ago.

But Curiosity did quite a bit of science work before getting to Yellowknife Bay. Leshin and her colleagues looked at the results of Curiosity's first extensive Mars soil analyses, which the 1-ton rover performed on dirt that it scooped up at a sandy site called Rocknest in November 2012.

Using its Sample Analysis at Mars instrument, or SAM, Curiosity heated this dirt to a temperature of 1,535 degrees Fahrenheit (835 degrees Celsius), and then identified the gases that boiled off. SAM saw significant amounts of carbon dioxide, oxygen and sulfur compounds — and lots of water on Mars.

SAM also determined that the soil water is rich in deuterium, a "heavy" isotope of hydrogen that contains one neutron and one proton (as opposed to "normal" hydrogen atoms, which have no neutrons). The water in Mars' thin air sports a similar deuterium ratio, Leshin said.

"That tells us that the dirt is acting like a bit of a sponge and absorbing water from the atmosphere," she said.

At left, a closeup view of the Mars rock target Rocknest taken by the Curiosity rover showing its sandy surface and shadows that were disrupted by the rover's front left wheel. At right, a view of Mars samples from Curiosity's third dirt scoop after it was seived. Image released Sept. 26, 2013

Some bad news for manned exploration
SAM detected some organic compounds in the Rocknest sample as well — carbon-containing chemicals that are the building blocks of life here on Earth. But as mission scientists reported late last year, these are simple, chlorinated organics that likely have nothing to do with Martian life

Instead, Leshin said, they were probably produced when organics that hitched a ride from Earth reacted with chlorine atoms released by a toxic chemical in the sample called perchlorate.

Perchlorate is known to exist in Martian dirt; NASA's Phoenix lander spotted it near the planet's north pole in 2008. Curiosity has now found evidence of it near the equator, suggesting that the chemical is common across the planet. (Indeed, observations by a variety of robotic Mars explorers indicate that Red Planet dirt is likely similar from place to place, distributed in a global layer across the surface, Leshin said.)

The presence of perchlorate is a challenge that architects of future manned Mars missions will have to overcome, Leshin said.

"Perchlorate is not good for people. We have to figure out, if humans are going to come into contact with the soil, how to deal with that," she said.

"That's the reason we send robotic explorers before we send humans — to try to really understand both the opportunities and the good stuff, and the challenges we need to work through," Leshin added.

A wealth of discoveries
The four other papers published in Science today report exciting results as well.

For example, Curiosity's laser-firing ChemCam instrument found a strong hydrogen signal in fine-grained Martian soils along the rover's route, reinforcing the SAM data and further suggesting that water is common in dirt across the planet (since such fine soils are globally distributed).

Another study reveals more intriguing details about a rock Curiosity studied in October 2012. This stone — which scientists dubbed "Jake Matijevic" in honor of a mission team member who died two weeks after the rover touched down — is a type of volcanic rock never before seen on Mars.

However, rocks similar to Jake Matijevic are commonly observed here on Earth, especially on oceanic islands and in rifts where the planet's crust is thinning out.

"Of all the Martian rocks, this one is the most Earth-like. It's kind of amazing," said Curiosity lead scientist John Grotzinger, a geologist at the California Institute of Technology in Pasadena. "What it indicates is that the planet is more evolved than we thought it was, more differentiated."

The five new studies showcase the diversity and scientific value of Gale Crater, Grotzinger said. They also highlight how well Curiosity's 10 science instruments have worked together, returning huge amounts of data that will keep the mission team busy for years to come.

"The amount of information that comes out of this rover just blows me away, all the time," Grotzinger told SPACE.com. "We're getting better at using Curiosity, and she just keeps telling us more and more. One year into the mission, we still feel like we're drinking from a fire hose."

The road to Mount Sharp
The pace of discovery could pick up even more. This past July, Curiosity left the Yellowknife Bay area and headed for Mount Sharp, which rises 3.4 miles (5.5 kilometers) into the Martian sky from Gale Crater's center.

Mount Sharp has been Curiosity's main destination since before the rover's November 2011 launch. Mission scientists want the rover to climb up through the mountain's foothills, reading the terrain's many layers along the way.

"As we go through the rock layers, we're basically looking at the history of ancient environments and how they may be changing," Grotzinger said. "So what we'll really be able to do for the first time is get a relative chronology of some substantial part of Martian history, which should be pretty cool."

Curiosity has covered about 20 percent of the planned 5.3-mile (8.5 km) trek to Mount Sharp. The rover, which is doing science work as it goes, may reach the base of the mountain around the middle of next year, Grotzinger said.

This self-portrait, composed of more than 50 images taken by Curiosity's MAHLI camera on Feb. 3, 2013, shows the rover at the John Klein drill site. A drill hole is visible at bottom left.

NASA's Mars rover Curiosity has revealed no trace of methane, a potential sign of primitive life, on the Martian surface, contradicting past evidence of the gas spotted by spacecraft orbiting the Red Planet, researchers say.

The Mars methane discovery, or rather the lack thereof, adds new fuel to the debate over whether the gas is truly present on Mars. And not all scientists are convinced that methane is missing on Mars.

The first and only attempts to search for life on Mars were the Viking missions, launched in 1975. Those probes failed to find organic compounds in Martian soils, apparently ruling out the possibility of extant life on the Red Planet.

But in the past decade, probes orbiting Mars and telescopes on Earth have detected what appeared to be plumes of methane gas from the Red Planet. The presence of colorless, odorless, flammable methane on Mars, the simplest organic molecule, helped revive the possibility of life once existing, or even currently living, just below the planet's surface.

On Earth, much of the methane in the atmosphere is released by life-forms, such as cattle. Scientists have suspected that methane stays stable in the Martian atmosphere for only about 300 years, so whatever is generating this gas did so recently.

Now, the new findings from NASA's Curiosity rover unveiled online today (Sept. 19) in the journal Science suggest that, at most, only trace amounts of methane exist on Mars.

"Because methane production is a possible signature of biological activity, our result is disappointing for many," said study lead author Christopher Webster, an Earth and planetary scientist at NASA's Jet Propulsion Laboratory in Pasadena, Calif.

But the findings still puzzle scientists.

"It's a mystery surrounded by an enigma here," said imaging physicist Jan-Peter Muller of University College London, who is a Curiosity rover science team member but is not one of the authors of this latest Mars methane study. "This clearly contradicts what has been measured from space and from Earth."

Methane mystery on Mars
The Curiosity rover has analyzed the surface and atmosphere of Mars with an arsenal of advanced scientific instruments ever since its spectacular landing on Mars in August 2012. Measurements from the rover's Tunable Laser Spectrometer, a device specially designed for measuring the gas on Mars, say the most methane that could currently exist in the Martian atmosphere is 1.3 parts per billion by volume. [Latest Mars Photos by the Curiosity Rover]

"Based on earlier observations, we were expecting to land on Mars and measure background levels of methane of at least several parts per billion, but saw nothing," Webster told SPACE.com.

When the researchers first looked for methane using Curiosity, they found strong signals that they quickly realized were coming from the little methane that they had taken with them, Webster said — that is, "'Florida air' that had leaked into one chamber during the long prelaunch activities. This contamination has been removed in stages, but each attempt to look for methane from the Mars atmosphere has resulted in a non-detection."

The original plan of the researchers was to analyze the carbon isotope ratios of methane on Mars to get insight on whether that gas could be biologically produced. "However, the lack of significant methane has denied that latter experiment," Webster said.

This new measurement is about six times lower than previous estimates of methane levels on Mars. Webster and his colleagues suggest this severely limits the odds of methane production by microbes below the surface of Mars or from rock chemistry.

"It's an excellent piece of science," Muller told SPACE.com. "However, it's not to say that what is measured 1 meter (3 feet) above the ground is representative of the atmosphere in total — that's a matter of interpretation, not necessarily a matter of fact."

Is the methane hiding?
For instance, past measurements of methane in the atmosphere of Mars analyzed a region much higher above the surface, "so these might be very different measurements," Muller said. "It does leave a little wiggle room in terms of interpretation."

Moreover, when it comes to places on Earth where methane leaks out, scientists can detect large volumes of methane right at the plumes but practically none away from them, Muller said.

"It's difficult to know whether the null measurement from Curiosity has to do with being in the wrong place at the wrong time, or whether it is representative of Mars," Muller said.

"We are often asked if our measurements at Gale Crater represent the planet as a whole," Webster noted. "We remind others that the lifetime of methane on Mars is very long, about 300 years, compared to the short mixing time — months — for the whole atmosphere, so we feel our measurement does represent the global background value."

Curiosity experiment may hold the key
The Sample Analysis at Mars suite of instruments on Curiosity has yet to conduct a "methane enrichment" experiment that will increase the sensitivity of the rover's Tunable Laser Spectrometer even further — by a factor of at least 10, Webster said. "It's possible that we may then see methane at extremely low levels — or, alternatively, we will not, and our upper limit will go down much further," he added.

The ExoMars spacecraft, planned for launch in 2016, will study the chemical composition of Mars' atmosphere to learn more about any methane there.

"It can look at the vertical distribution of methane on Mars, see if it's lofted some way high up in the atmosphere or if it's near the ground," Muller said. "If it's near the ground, that's likely reflective of it seeping out of the ground; if it's high in the atmosphere, some exotic photochemical process may be responsible."

Webster stressed that Curiosity will continue its mission to assess the habitability of Mars.

"The Curiosity rover will continue to make its measurements of both atmosphere and rock samples to discover if organics other than methane exist on Mars," Webster said. "To that end, the jury is still out, as these important measurements are being made in a series of studies that will extend many months into the future. Stay tuned!"

A penny on Mars has grown rich with red dust while riding on a NASA rover.

An ultra high-resolution photo recently sent back from the Red Planet revealed the red cent is covered in Mars dust, despite it being mounted vertically on the space agency's Curiosity rover for the past 14 months. The penny's patina however, was not the primary focus of the photograph that captured its current condition.

"I'm so proud of how beautifully the camera has performed on Mars," said R. Aileen Yingst, the senior scientist at the Planetary Science Institute in Tucson and deputy principal investigator for the Mars Hand Lens Imager, or MAHLI for short. "I can't wait to apply this newly available capability to real geologic targets on our way to Mount Sharp." [Amazing Mars Rover Curiosity's Martian Views (Latest Photos)]

The six-wheeled Curiosity, which is also referred to as the Mars Science Laboratory (MSL), landed inside Mars' Gale Crater in August 2012 and then spent the next 11 months being checked out while starting science investigations in an area near where it had touched down. It was there that Curiosity achieved its major science objective, finding the evidence for a wet environment that could have supported ancient microbial life.

Now into the second year of its planned two-year mission, the rover is trailblazing a path to the base of Mount Sharp, a 3.4-mile-high (5.5-kilometer) mountain that rises from the crater's center. Once there, Curiosity will resume its study into how the Mars' environment changed and evolved.

The coin, which was minted during the first year President Abraham Lincoln was depicted on the front of the one cent piece, was flown to Mars as part of a calibration target for the MAHLI. The rover was equipped with the hand lens to take color close-up images of rocks and surface materials at a very high resolution.

At 14 micrometers per pixel, the photo of the penny was a demonstration of the imager's best-capable return, Yingst said. A micrometer, also referred to as a micron, is about 0.000039 inches.

The image was obtained as part of a test. It was the first time that the rover's robotic arm placed the camera close enough to a target such that it could obtain the MAHLI's highest-possible resolution. Earlier MAHLI images, which focused on Martian rocks, were taken at 16 to 17 microns per pixel.

It was not however, the highest resolution photo taken on Mars. Credit for that record goes to the optical microscope on NASA's Phoenix Mars Lander, which touched down in 2008. As a microscope though, fine-grained samples had to be delivered to it to be imaged, whereas the MAHLI on Curiosity can be deployed to look at the geologic materials in their natural setting.

The image of the penny was acquired on Oct. 2, Sol 411, or the 411th Martian day that Curiosity has been exploring Gale Crater.

As the photo shows in fine detail, the copper coin is dated for 1909. What it does not reveal is what makes the penny particularly rare: the initials ("VDB") of the coin's designer, Victor David Brenner, which are etched on the reverse.

Brenner's initials were deemed to be too prominent, and as such were removed from subsequent mintings within days of the penny's initial release.

Ken Edgett, who picked out and purchased the penny with his own funds, said that he selected the coin to continue a tradition that began on Earth.

"The penny is on the MAHLI calibration target as a tip of the hat to geologists' informal practice of placing a coin or other object of known scale in their photographs," Edgett, principal investigator with Malin Space Science Systems, said prior to Curiosity landing. "Of course, this penny can't be moved around and placed in MAHLI images; it stays affixed to the rover."

The penny was also intended as an outreach tool, he said.

"Everyone in the United States can recognize the penny and immediately know how big it is, and can compare that with the rover hardware and Mars materials in the same image," Edgett said. "The public can watch for changes in the penny over the long term on Mars."

NASA's Mars rover Curiosity rebooted its software after an unexpected glitch late last week, but the six-wheeled robot is now doing fine on the surface of the Red Planet, NASA officials say.

The reboot — also known as a "warm reset" — occurred on Thursday (Nov. 7), less than five hours after Curiosity's handlers had uploaded new flight software to the 1-ton rover. It was the first time Curiosity had experienced such a fault-related reboot since landing on Mars in August 2012, officials said.

"Telemetry later downlinked from the rover indicates the warm reset was performed as would be expected in response to an unanticipated event," Curiosity project manager Jim Erickson, of NASA's Jet Propulsion Laboratory in Pasadena, Calif., said in a statement.

Warm resets are triggered when a spacecraft's flight software identifies a problem with one of its operations. While mission team members are still working to figure out what exactly happened, the glitch does not appear to pose any serious problems.

"So, that happened. Had a warm reset yestersol. I'm healthy. Spending the weekend awaiting new instructions," NASA officials said Friday (Nov. 8) via Curiosity's official Twitter feed, @MarsCuriosity. (A "sol" is one Martian day, which is about 40 minutes longer than a day here on Earth.)

The 1-ton Curiosity rover touched down inside Mars' huge Gale Crater on Aug. 5, 2012, kicking off a planned two-year surface mission to determine if the Red Planet has ever been capable of supporting microbial life. The robot has already achieved that goal, finding that an area near its landing site called Yellowknife Bay was indeed habitable billions of years ago

Curiosity is now on its way to the towering Mount Sharp, which rises 3.4 miles (5.5 km) into the Martian sky from Gale Crater's center. Mission scientists want the rover to climb up through Mount Sharp's foothills, reading the history of Mars' changing environmental conditions as it goes.

The trek from Yellowknife Bay to the base of Mount Sharp covers about 5.3 miles (8.6 km). Curiosity embarked upon this journey in early July and is about one-third of the way to the mountain, which has been its primary destination since before the rover's November 2011 launch

NASA's Mars Rover has captured the image of a rock that looks just like an iguana.

The iguana doppleganger was first spotted by the website UFO Sightings Daily who found the photograph on NASA's archives of dozens of images of the barren landscape surrounding the Curiosity Rover.

The reptile-shaped rock is not the first "animal" to be found on Mars. A rock shaped like a rat was discovered earlier this year.

"This is not the first animal found on Mars, actually there have been about 10-15 to date," UFO Sightings Daily coordinator Scott C. Warring told Canadian news site agoracosmopolitan.com. "I even found a rock that moved four times in four photos...then vanished on the fifth."